1. Field of the Invention
This invention relates to an oral airway and more particularly to an oral airway which truly represents an improvement in the oral airway art.
2. Description of the Related Art
In modern anesthesia practice, oral airways are used primarily for two reasons. The first reason is that after intubation of the trachea, an oral airway is placed to prevent a patient from biting down on the endotracheal tube and thus occluding the endotracheal tube. The second and primary reason for the use of an oral airway in the practice of anesthesia is to elevate the tongue against the floor of the mouth to create a larger opening in the mouth to facilitate the utilization of positive pressure ventilation using an anesthesia mask after a patient has been given medications to induce general anesthesia. The drugs normally used to induce general anesthesia may greatly decrease or altogether stop the patient's own spontaneous respiratory effort. Therefore, the Anesthesia Practitioner must immediately begin assisting or controlling the patient's ventilation.
It has been noted that patients undergoing general anesthesia have occasional difficulties in maintaining the patient's airway and the ability to ventilate the patient. It has been observed that patients of all ages were difficult to ventilate with an anesthesia mask after induction of general anesthesia. This has happened even after proper placement of the recommended size of oral airway. Anyone who has practiced anesthesia for some time has experienced the same difficulties. Anesthesia Practitioners are all taught the “tricks of the trade” in how to ventilate patients after induction of general anesthesia including a variety of physical adjustments to the anesthetized patient such as elevation of the jaw and extension of the patient's neck. If the patient cannot be adequately ventilated after induction of general anesthesia, life-threatening problems may develop such as hypoxia, hypercarbia, cardiac arrhythmias and even death.
Once general anesthesia has been induced, one of the main impediments to adequately ventilating a patient with positive pressure ventilation, after placement of an oral airway, is the relaxation of the soft tissue structures in the hypo-pharynx. These structures tend to collapse, thus obstructing airflow. This inward collapsing occurs both front to back and side to side, thus greatly decreasing the size of the oral opening through which the Anesthesia Practitioner may ventilate the patient. This anatomical relaxation is fairly consistent with every patient who undergoes a general anesthetic. However, there is a physical characteristic of some patients which greatly increases the difficulty of mask ventilation—that characteristic is obesity. Applicant has noted the increasing incidence of obesity in both the pediatric and adult population. These obese patients present an increased level of difficulty to the Anesthesia Practitioner in the area of airway management. Obese patients tend to have larger, thicker tongues along with more redundant soft tissue in the oropharyngeal area. Obese patients also tend to have thicker necks, so it is more difficult to hyperextend the neck and lift the jaw to facilitate adequate ventilation after general anesthesia is induced. In discussions with Anesthesia Practitioners, the inventor has perceived a common concern that the oral airways currently available do not adequately address the growing problem of obesity in the population.
As stated, it is well known to utilize an oral airway for the purpose of aiding the breathing of unconscious patients. Reference may be made to U.S. Pat. No. 2,599,521, which issued Jun. 3, 1952, to R. A. Berman, for a description of a conventional oral airway now known in medical practice as the Berman Oral Airway. The Berman Oral Airway, and later devices modeled after it, is employed in the practice of anesthesia and other areas of respiratory medicine by insertion of the oral airway into the mouth and pharynx of a patient to provide a channel for respiratory purposes, particularly in unconscious patients such as those who have been administered a general anesthetic. It is the purpose of the oral airway to prevent respiratory obstruction by preventing collapse of the pharyngeal tissues and/or obstruction of the pharynx by the tongue.
The Berman Oral Airway and later devices are available to the medical professional in a number of different sizes for use in all sizes of patients from premature infants to large adults. However, each size constitutes a unitary member which may not itself be adjusted in size, shape, or contour. Thus, conventional airways are substantially rigid structures which may not be altered in use to fit particular patients, particular problems, or unusual anatomic anomalies or structures. The Berman Oral Airway has served Anesthesia Practitioners well for many years, but the physical characteristics of patients have changed since 1952 while the Berman Oral Airway remains the same.
The Berman Oral Airway comes in various sizes from 40 mm to 100 mm in incremental steps of 10 mm (i.e., 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm). These sizes are roughly correlated to general anatomic dimension described as the distance from the exterior of the front teeth to the back of the oropharynx. So, correspondingly, a 40 mm Berman Oral Airway is probably an appropriate size for a premature infant whereas a 100 mm Berman Oral Airway is probably appropriate for a large adult, and a 90 mm Berman Oral Airway is generally used on a medium adult patient. If the patient is very obese and has a thick tongue and has a large amount of soft tissue in the oropharynx, the 90 mm oral airway may not adequately elevate the tongue because it is not wide enough side to side to provide enough support for the tongue. In this case, a 100 mm Berman Oral Airway (which is wider side to side) may provide the additional support for the tongue that is needed to open the airway, but it cannot be used because the longer structure of the airway (100 mm) may not fit in the patient's mouth. The 100 mm oral airway would extend too far outside of the patient's mouth, thus placing an anesthesia mask over the patient's face to obtain a good mask seal in order to ventilate the patient with positive pressure would be very difficult, if not impossible. The usual scenario is someone who is of very short stature and very obese. These people many times need the width and depth of a 100 mm Berman Oral Airway, but the length of an 80 mm Berman Oral Airway. This would greatly facilitate the ability to ventilate this patient after induction of general anesthesia. This problem has been overcome in the past by actually inserting two 80 mm Berman Oral Airways on these types of patients or sometimes one 90 mm Berman Oral Airway and one 80 mm Berman Oral Airway. In this way you are able to achieve enough side to side tongue support to adequately ventilate the patient until you are ready to place an LMA or intubate the patient. Inserting two airways into the patient is sometimes adequate but can be awkward. Therefore, a new type of airway is needed for these patients.